A new instrument for drainage or injection of fluid within subretinal space

Purpose: To describe a new instrument, the subretinal aspiration and injection device (SR-AID), designed to facilitate the controlled external drainage or injection of fluid in the subretinal space. Methods: The SR-AID is formed by an assembly of a probe, handle body, and a driving unit. The curved conduit within the probe segment forms a curved tunnel and acts as a guide along which a needle moves back and forth. The feasibility of fluid injection beneath the attached retina was tested in animal eyes. The efficacy of subretinal fluid drainage with the SR-AID were assessed in six cases of clinical retinal detachment. Results: External approach to the subretinal space under ophthalmoscopic monitoring can be achieved by oblique angle penetration of the scleral wall with a needle from the SR-AID. Fluid was injected successfully into the subretinal space in three of six rabbit eyes and in two of two pig eyes. The mean duration required for the drainage of subretinal fluid with the SR-AID was 127 seconds. There was no incidence of significant subretinal hemorrhage or retinal perforation in the animal experiments and in human cases. Conclusion: Our case series suggests that the SR-AID provides an efficient and safe means of access to the subretinal space.